In such a situation, i.e when additional digital data have to be added before transmission to an existing coded bitstream, the simplest solution is to decode said bitstream before carrying out said addition. The modified bitstream is then re-coded and transmitted. Unfortunately, a full decoding can generally be considered as expensive, as it requires a decoder and an encoder. Moreover, re-encoding with re-estimated modes and vectors may introduce artefacts on the areas left untouched by the logo addition.